Post-crystalline deformation is indicated by the following microstructures.
(1) A straight or S-shaped Si discordant with Se. If the Si and the Se represent the same generation of the s-surface, this microstructure indicates a post-crystalline rotation of the porphyroblast
(2) A straight Si of a porphyroblast continuing into or discordant
with a crenulated Se. The crenulation is then postcrystalline with respect to the porphyroblast.
(3) A strongly asymmetric swerving of the cleavage around a porphyroblast is indicative of post-crystalline rotation.
(4) Microstructures showing presence of undulatory extinctions, deformation bands, deformation lamellae and Boehm lamellae in quartz, microfolds and kink bands in micas and chlorite, deformation twins, twin lamellae offset by microfaults, separation of grain fragments across tension fractures, grains disseeted by parallel shear fractures with slip and rotation of the slices and folding or boudinage of the fine rutile or sillimanite needles occurring as inclusions in quartz grains indicate postcrystalline deformation.